The point was simply that your earlier post did not seem relevant to the
property of interest, which was propagation speed rather than amount of heat
transferred. At least intuitively (and quite possibly
non-quantum-mechanically, as I said), the latter should be a smoothly
varying function of the speed of the molecules and the distance between
them, but one which does not reach zero unless either the speed is zero (no
temperature gradient, which is not the case at hand) or the distance is
infinite (no substance, which is also not the case at hand).
Or, to put it another way, the propagation speed of heat is not the same as
the speed of temperature increase at some point - just as the speed of light
is unaffected when you reduce the amount of light energy reaching a location
by placing a (coarse, to avoid QM effects) grid between the source and the
destination. The heat capacity of the substance (analogous to the blocking
percentage of the grid) determines *how much* energy reaches a given point
by a given time, but not when the *first* energy arrives.
- bill
Brian Inglis <Brian.dot.Inglis at SystematicSw.ab.ca> wrote in message
news:1dETOAvAh1=E39kwX3lwJ8QmH1cl at 4ax.com...
> You can say that the additional low frequency energy increases
> the velocity/momentum/kinetic energy of the molecules, or
> increases the radius of the spatial distribution of the molecular
> wave function. But I was trained in chemistry, and we used the
> simplest available model to describe the properties of interest.
>> On Sun, 24 Oct 1999 16:15:13 -0400, "Bill Todd"
> <billtodd at foo.mv.com> wrote:
>> >I already expressed the opinion that propagation faster than c was
unlikely.
> >However, propagation at close to c seems more reasonable: my distinct
> >impression is that thinking of molecules 'bouncing against' other
molecules
> >as opposed to interacting with them via their associated (EM, gravitic,
> >etc.) fields may be naive - and while the fields interact more strongly
as
> >the molecules get closer together (causing their relative speed and
> >separation to affect the *amount* of heat transferred), they *begin* to
> >interact as soon as the molecules move at all (or, in the extreme, the
> >farthest molecule *begins* to be affected - minutely, certainly
> >indetectibly, but affected, at least via classical ED, though perhaps QED
> >may cloud the issue - as soon as the first molecule starts to move, plus
a
> >c-imposed delay).
> >
> >- bill
> >
> >Brian Inglis <Brian.dot.Inglis at SystematicSw.ab.ca> wrote in message
> >news:5HASOHZAgVLBVaW0NUFxy4Jisy6L at 4ax.com...> >> Think physics and reality. Temperature is just a measure of heat,
> >> which is a result of molecular motion. Applying energy to some
> >> substances causes the molecules to bounce around more: we
> >> perceive this as heat and measure it as temperature.
> >>
> >> Heat propagates as molecules transmit energy to other molecules
> >> by bouncing against them, so heat conduction is limited by the
> >> speed at which these molecules can bounce, and transmit energy to
> >> adjacent molecules.
> >>
> >> It's a lot slower and less efficient than shipping the energy
> >> around as E-M radiation, to affect the target molecules directly.
> >>
> >>
> >> Apply too much energy to any real substance and you don't get
> >> heat transfer, you get a change in the substance: a chemical
> >> reaction, an absorption of energy, not heat transfer.
> >>
> >> Theoretically, you can calculate anything, but if you don't take
> >> into account the limitations of some conductive substance, it
> >> probably isn't heat transfer that you're calculating, just some
> >> ideal mathematical construct unrelated to reality.
> >>
> >> On Sat, 23 Oct 1999 16:31:28 -0400, "Bill Todd"
> >> <billtodd at foo.mv.com> wrote:
> >>
> >> >I'm not sure that's relevant: the *degree* to which the top-side of
the
> >> >frying pan heats up is related to the heat capacity (if I recall the
term
> >> >correctly - or perhaps it's specific heat?) of the frying pan - i.e.,
the
> >> >more heat it can absorb per unit volume for a given temperature rise,
the
> >> >slower the temperature of a portion far from the heat source will
rise.
> >But
> >> >that doesn't prohibit instantaneous propagation (which would mean that
> >the
> >> >far portion's temperature rise would *begin* immediately, regardless
of
> >how
> >> >slow it was).
> >> >
> >> >- bill
> >> >
> >> >Steven Vogel <spamvogel at iconn.net> wrote in message
> >> >news:38112AAB.1E02 at iconn.net...> >> >> Naturally, you're correct. As an experiment to prove your point,
you
> >> >> could turn the burner on your stove on high. After ten minutes, put
a
> >> >> cast iron pan on the burner and put your hand on the top of pan
right
> >> >> away for ten seconds. After ten minutes, have the poster that said
> >that
> >> >> heat travels faster than the speed of light put their hand on the
top
> >of
> >> >> the pan for ten seconds.
> >> >>
> >> >> The person who doesn't scream has the better grasp of reality.
> >> >>
> >> >> Bill Todd wrote:
> >> >> >
> >> >> > If heat in a substance does in fact propagate via the interaction
of
> >> >> > particles and EM fields, it's hard to see how it could do so at a
> >speed
> >> >> > faster than c.
> >> >> >
> >> >> > - bill
> >> >> >
> >> >> > Erik Max Francis <max at alcyone.com> wrote in message
> >> >> > news:3810DBC3.3463B0BB at alcyone.com...> >> >> > > Ronnie Sahlberg wrote:
> >> >> > >
> >> >> > > > Well actually I am, but the equation is faulty. It is only a
good
> >> >> > > > approximative model
> >> >> > > > of the physic characteristics of heat, not an exact
description
> >of.
> >> >> > >
> >> >> > > Well, no kidding.
> >> >> > >
> >> >> > > > Examine function describing heat distribution along the
string.
> >> >> > > > Examine value of this function at t=epsilon (epsilon
approaching
> >0)
> >> >> > > > especially "interesting" are the values of this function
> >infinitely
> >> >> > > > far
> >> >> > > > from
> >> >> > > > point p. It is small but non-zero.
> >> >> > >
> >> >> > > This is doing the equation, not doing the physics.
> >> >> > >
> >> >> > > --
> >> >> > > Erik Max Francis | icq 16063900 | whois mf303 | email
> >max at alcyone.com> >> >> > > Alcyone Systems | irc maxxon (efnet) | web
> >> >http://www.alcyone.com/max/> >> >> > > San Jose, CA | languages en, eo | icbm 37 20 07 N 121 53 38
W
> >> >> > > USA | Fri 1999 Oct 22 (43%/950) | &tSftDotIotE
> >> >> > > __
> >> >> > > / \ Do not seek death. Death will find you.
> >> >> > > \__/ Dag Hammarskjold
> >> >
> >>
> >> Thanks. Take care, Brian Inglis Calgary, Alberta, Canada
> >> --
> >> Brian_Inglis at CSi.com (Brian dot Inglis at SystematicSw dot ab dot ca)
> >> use address above to reply
> >
>> Thanks. Take care, Brian Inglis Calgary, Alberta, Canada
> --
>Brian_Inglis at CSi.com (Brian dot Inglis at SystematicSw dot ab dot ca)
> use address above to reply
